The Democratic rift over welfare reform, pitting President Bill Clinton against his party's liberal wing and even its very chairman, is casting a genuine cloud of controversy over the convention which opens today - the first in Chicago since the bloodstained gathering of 1968 that has won the city an unwelcome niche in American political infamy.

In interviews this weekend, Mr Clinton acknowledged continuing deep tensions in his party over his signature last week of a welfare reform bill that removes federal guarantees of help for poor children dating back to the New Deal of Franklin Roosevelt, the Democrats' greatest political hero of all.

Patricia Ireland, president of the National Oragnization for Women, denounced Mr Clinton and accused him of caving in to religious and political extremists. "While some of us may hold our noses and vote for President Clinton, many of us will refuse to lift a finger or contribute a penny toward his re- election." she said. "We know he is at best our option this year, not our answer."

The disagreement seems bound to surface during four days of confabulation that otherwise will be a re-coronation of a sitting President. "We're not going to push anyone into a corner," Mr Clinton said, referring to scheduled speakers such as the civil rights leader Jesse Jackson and the party's chairman, Senator Christopher Dodd of Connecticut, both of whom harshly criticised him.

But despite this argument, the differences far outnumber the similarities with 28 years ago, when the Democrats last gathered on the shores of Lake Michigan, and watched the national agony over the Vietnam War turn downtown Chicago into an urban battlefield. For all the controversy within Democratic ranks, welfare reform is overwhelmingly popular among the public. It is unlikely to be more than a sideshow on the path to what Democrats hope will be victory this November and the first time a sitting President from their party has won a second term since FDR in 1936.

Chicago, too, is on its best behaviour. The city has been spruced and the police, fresh from "sensitivity training", are under instructions to be as gentle as possible. "There's not going to be any confrontation," says Richard M Daley, Chicago's mayor and son of Richard J Daley, the powerbroker supreme who ruled Chicago for two decades and ordered the savage crackdown against the demonstrators of 1968.

Two designated protest areas have been set up close to the inner Westside sports arena where the convention will be held.

Inside the hall, welfare aside, the convention promises to be uneventful and as carefully packaged as its Republican counterpart earlier this month - so uneventful that a presidential train trip has been scheduled across the Midwest for its first three days, during which Mr Clinton will be making policy pronouncements on crime, education and the environment, to create at least the illusion of news.

On Friday, the day after Mr Clinton delivers an acceptance speech his aides are billing as a "State of The Union II", he and Vice-President Al Gore will repeat the post-convention bus tour that was a highlight of the 1992 campaign, this time spending two days travelling through Illinois, Kentucky and Tennessee.

Inside the arena, however, the Democrats will have a job to match the spark generated by the Republicans in San Diego. No former presidents, no General Colin Powell will be providing fireworks, and it was not even clear whether Mario Cuomo, former New York Governor and the party's most inspirational speaker - but a bitter foe of the welfare bill - would take the podium here.

Even so, the Republicans' post-convention surge is beginning to fade. A Newsweek poll yesterday put Mr Clinton's lead over his Republican challenger Bob Dole at 7 per cent, up from only 2 per cent immediately after San Diego.

The divided loyalties within the Democratic Party have not been lost on Mr Dole, who has tried to capitalise on them. "Just imagine what he'll do if he were somehow to win a second term - his liberalism unrestrained by the need to face the American people in another election," Mr Dole said.

After Chicago, Democratic planners hope the party's lead will be back in double figures - an insuperable margin if previous elections are any yardstick.